I am not taking up for the dad in the OP's post. But it reminded me of how I trained my son not to walk away when I was looking at things in the store. He was the worse. He was about 4 yrs long past the age when a child should be minding a parent. Every chance he got he snuck off in the store. I couldn't concentrate for watching him. He climbed out of the buggy constantly.
It had been a particularly trying day. He was, as usual, doing his own thing as dad and I shopped. I had finally had enough, His dad was just turning to drag him back when I caught his hand and said I'm done let him go.
I told my husband to follow me. We moved over to where he could no longer see us if he turned around. We proceeded to hide and watch. After about 5 minutes he starts looking and looking and looking. We had an eye on him the entire time. All of a sudden you could see him very panicked, looking around. He opens his mouth to scream and has a full-fledged panic attack. Loses his breath falls on the floor and turns blue.
From that day on I never had to worry about him wandering away in a store, he was glue, never took his eyes off me in any public place.
That may seem horrible and cruel to some. I never did anything near as bad to my kids as what they would have suffered as consequences in the big bad world. that is what parents reluctant to discipline don't seem to realize. The tragedy is when kids suffer the very worse consequences of the reluctance to discipline.